Relationship of Methylation within Upper Stream Region of Transcription Starts Site of HOXA5 Gene with Neural Tube Defects.

Objective To investigate the relationship between the methylation level of transcription starts site (TSS) upper stream of homeobox gene and the neural tube defects (NTDs). Methods A case-control study of two stages was designed. In the first stage,10 cases and 8 controls were extracted,in whom Illumina Infinium Human Methylation 450 k genome-wide beadchip was used for the quantification of DNA methylation levels of brain and spinal tissue. In the second stage,differentially methylated region within HOXA5 gene was detected with a larger numbers of samples (52 cases and 23 controls). DNA of brain or spinal tissue was extracted,and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry technique of MassARRAY platform was employed for the validation of differentially methylated region of HOXA5 gene. Results In the first stage,27 CpG sites within TSS region of HOXA5 gene were found to be significantly hyper-methylated in case group compared to control group (P<0.05). In the second stage,a total of 10 CpG sites were analyzable within the differentially methylated region in the first stage. In the NTD case group,spinal bifida subgroup,and anencephaly subgroup,there were 7,6,and 2 sites with significantly higher methylation levels than that of control group (P<0.05). The average methylation level of TSS upper stream region within HOXA5 gene was higher in case group than control group [case group:(31.3±13.9)%,control group:(21.4±9.7)%],and the odds ratio after adjusting gender of fetus and pregnant week was 1.09 (1.03-1.16). Conclusion Hypermethylation within TSS upper stream region of HOXA5 gene in fetus is associated with a higher risk of NTDs.

High-risk human papillomavirus infection associated with telomere elongation in patients with esophageal squamous cell carcinoma with poor prognosis.

BACKGROUND: Telomere maintenance is crucial in carcinogenesis and tumor progression. The results of a previous study from the authors indicated that infection with high-risk human papillomavirus (HR-HPV) types 16, 18, and 58 was a risk factor for esophageal squamous cell carcinoma (ESCC) in the Shantou region of China. In the current study, the authors explored the association between HR-HPV infection, telomere length (TL), and DNA methylation and their significance in the prognosis of patients with ESCC. METHODS: TL and DNA methylation were analyzed by real-time polymerase chain reaction and methylation-specific polymerase chain reaction in 70 cases of ESCC tumor (T) and paired nontumor (NT) tissues and 50 cases of normal esophagus (NE). The prognostic value of TL and DNA methylation in ESCC was analyzed. RESULTS: TL gradually decreased from NE to NT to T tissue. TL in tumor tissue (T-TL) was found to be longer in tissue that was positive for HR-HPV compared with negative tissue and was found to be positively associated with viral load (Spearman correlation, 0.410; P = .037) and integration (represented by the ratio of HR-HPV E2 to E6/E7 genes; P = .01). The DNA methylation ratio of human telomerase reverse transcriptase was more prevalent with long (≥ 0.7) compared with short (< 0.7) T-TL and was positively correlated with T-TL (Spearman correlation, 0.318; P = .007) and HR-HPV integration (P = .036). Furthermore, Cox proportional hazards modeling revealed a high ratio of T-TL to NT-TL (≥ 0.80) as a factor of poor prognosis, independent of other clinicopathologic variables. CONCLUSIONS: HR-HPV infection and integration related to telomere elongation and DNA methylation of human telomerase reverse transcriptase may be a potential biomarker of prognosis in patients with ESCC.

Status and significance of CpG island methylator phenotype in endometrial cancer.

BACKGROUND: Endometrial cancer is a common gynecologic malignant disease, but patients with advanced disease have a poor prognosis. The CpG island methylator phenotype (CIMP) involves hypermethylation targeted toward the promoters of multiple genes. OBJECTIVE: To investigate the role of epigenetic aberration of tumor-related genes in endometrial cancer. METHODS: The promoter methylation status of 5 genes was examined in 35 endometrial cancer tissues, 15 matched adjacent normal endometrial tissues (NET) from the same cancer patients, and 22 benign endometria from unaffected patients by methylation-specific PCR. CIMP positivity (CIMP+) was defined as concordant methylation of ≥3 genes. RESULTS: The methylation frequency of promoters for the 5 genes in the cancer tissues ranged from 37% for P16 to 57% for P14. Cancer and benign endometria, but not cancer and adjacent NET, significantly differed in methylation of P14, P16, ER, COX-2 and RASSF1A (p < 0.05). CIMP+ was frequent in cancer and adjacent NET (46 and 47%, respectively; p > 0.05), but absent in benign endometria. Moreover, CIMP+ was significantly correlated with methylation of P16 and COX-2 (r = 0.673 and 0.662, respectively; p < 0.001). CONCLUSION: CIMP+ is an important and frequent epigenetic event in endometrial cancer or adjacent NET, and may be a biomarker for predicting early carcinogenesis. COX-2 is a good representative gene of CIMP+ in this cancer.